How does your brain decide what’s worth remembering? What’s actually happening when you can’t recall someone’s name or where you parked your car?
In her book Remember, Lisa Genova explains the fascinating science of memory formation and why forgetting is actually a vital brain function. Drawing from her background in neuroscience, she breaks down complex processes into clear, actionable insights about remembering and forgetting.
Keep reading to discover why your memory works the way it does—and how to make it work better for you.
Overview of Remember (Lisa Genova)
Have you ever struggled to remember someone’s name at a party or forgotten where you parked your car? Are you worried that a memory lapse is a sign of Alzheimer’s? In Remember, Lisa Genova explores the complexity of human memory, demystifying why we remember and why we forget. She explains how memories are formed in the brain, what factors influence memory, and how understanding the science behind memory can help us better navigate both remembering and forgetting in our daily lives. She also reassures us that many types of forgetting are perfectly normal and even beneficial for cognitive function.
Genova holds a degree in biopsychology from Bates College and a PhD in neuroscience from Harvard University. Her best-selling debut novel Still Alice is about a professor dealing with early-onset Alzheimer’s, and it became an Academy Award-winning film. Her other novels include Left Neglected, Love Anthony, and Every Note Played. Remember, published in 2021, is her first nonfiction book.
We’ll first explore the types of memory, then discuss how memories are formed and how memory sometimes fails us. We’ll also discuss the impact of stress on memories, and we’ll provide some tips for how to improve your memory—as well as how to forget.
Types of Memory
Genova explains that memory is a process that involves encoding, consolidating, storing, and retrieving information. Genova describes several types of memory:
Working memory refers to the brain’s system for holding information in consciousness for brief periods of time. It operates in the prefrontal cortex (the front part of the brain) and can only hold a few pieces of information for 15-30 seconds. Most of it is then forgotten, but some memories transition from working memory into long-term memory, something you store in your brain for an indefinite, extended period.
Episodic memory refers to your memories of things that have happened. These include experiences like important life events and specific memories of things that have happened to you. Semantic memory, on the other hand, is fact-based knowledge not linked to a specific personal experience. This includes things like your vocabulary (remembering what words mean and how to use them) and general knowledge.
Genova also describes prospective memory, which is your memory of things you intend to do in the future. For example, if you plan to call your doctor at a certain time, remembering to do this when the time comes requires you to use your prospective memory. Episodic, semantic, and prospective memory are all types of declarative memory, or memories that you can consciously retrieve at will.
Finally, Genova discusses muscle memory, which she describes as the ability to remember how to do something. Like episodic memory and semantic memory, it’s a type of long-term memory. But, unlike the previous three we’ve discussed, muscle memory isn’t a type of declarative memory. Instead, you activate it unconsciously when you do something you’ve done many times before. For example, you don’t have to re-learn how to type every time you sit down in front of the computer: Your brain retains the information of how to move your body to achieve the desired result. Despite the name, muscle memory isn’t stored in your muscles, but in your brain.
How Memories Are Formed
Each type of memory is created in the same way. In this section, we’ll look at the process through which our brains create memories out of what we perceive.
According to Genova, memories are created through four basic steps in the brain: encoding, consolidation, storage, and retrieval. During encoding, your brain turns sensory input into a format that it can store.
During consolidation, your brain—specifically, your hippocampus, located in the middle of the brain—links this new information to existing neural patterns, or information you already know.
During storage, explains Genova, your brain changes structurally and chemically to keep these patterns in place. These changes can include the creation of new pathways between neurons and brain areas or even the formation of new neurons (neurogenesis).
Finally, during retrieval, you access the stored information as memory, writes Genova.
Genova explains that memories are not stored in a single location in the brain, but rather distributed throughout the neural networks that were active during the original experience of creating that memory. When you remember something, you’re not accessing a perfect recording but rather reconstructing the experience by reactivating these neural patterns. This explains why memory is both powerful and imperfect—it’s a dynamic process of reconstruction rather than a simple playback mechanism. Next we’ll explore the factors that come into play that lead us to remember or forget.
What Do We Remember?
Genova explains that we don’t encode and store all the information we perceive. We immediately forget—or don’t even notice—many things. In order to turn something into a memory, we have to pay attention to it. This means we’ll only remember things that catch our attention or that we consciously choose to pay attention to. This is why we usually ignore or forget things we’ve done that are automatic behaviors, like making coffee every morning or driving home from work. This is also why you’ll have more trouble remembering something if your attention to it is divided, so multitasking will make you less likely to form strong and accurate memories.
According to Genova, we’re also more likely to encode and remember things that elicit an emotional reaction. Emotion is what makes things meaningful to us, and it acts as a signal to the brain to encode what’s happening and store that information in our long-term memory. This is why we remember things that are linked to strong emotions better than those that feel neutral.
What we remember can also depend on the context in which we formed the memory. Genova explains that we’re better able to retrieve information when we’re in the same context in which we initially learned it. This can include physical location—it’s easier to remember something when you’re in the same place you were when you formed the memory. We also remember information better when our internal state matches the conditions present during initial learning. This includes both emotional states and physiological states. For example, we’re more likely to remember positive experiences when we’re in a good mood.
Sometimes though, we simply can’t remember something we mean to, or our memory is actually incorrect.
When Memory Fails
Experiencing a memory “failure” can be both frustrating and frightening, as we sometimes perceive it as a sign that our memories are degrading. Many view it as a sign of impending Alzheimer’s disease, especially those in older age groups. However, Genova explains that our brains are highly efficient, and they evolved to remember meaningful things and forget the meaningless. Much of what we forget—like routine daily activities or minor details—isn’t actually problematic, nor is it a sign of Alzheimer’s or dementia. Sometimes though, we forget things we care about, not because our memory is failing but because we haven’t provided our brains with the necessary inputs for memory creation and retrieval.
According to Genova, our episodic memories are fundamentally unreliable and prone to distortion. This unreliability begins at the encoding stage, as we can only remember what we notice and pay attention to in the first place, meaning our memories are inherently incomplete from the start. Distortion often happens at the consolidation stage: During this period, memories can be altered by imagination, beliefs, biases, dreams, other people’s memories, and various other influences.
Even after memories are stored, explains Genova, they remain susceptible to change. Over time, the neural networks that store a particular memory can weaken or go away entirely, which can weaken or delete that memory.
Finally, memories can also be distorted during retrieval, says Genova. Every time we retrieve a memory, we’re not playing back a recording but rather reconstructing the event. This reconstruction process often involves filling in gaps, reinterpreting details, and incorporating new information or perspectives. When we store the memory again after recall, we save this altered version, canceling out the original. This process means that frequently recalled memories, such as stories we tell often, can become increasingly distant from what actually occurred.
Why We Need to Forget
While normal memory loss can be frustrating, it also serves an important purpose. If we remembered everything in perfect detail, our brains would become crowded with information, making reasoning and remembering difficult. Genova challenges the common perception of forgetting as a passive, default process that only happens to us involuntarily. Instead, she presents forgetting as an active, purposeful, and often beneficial process. Forgetting routine details like what we ate for lunch yesterday or how much traffic we drove through this morning actually helps us function more effectively by clearing mental space for new, relevant information.
Both remembering and forgetting can be deliberate or accidental, and both are impacted by various factors. Next, we’ll explore stress’s influence on memory.
How Stress Impacts Memory
According to Genova, the activation of our stress response can affect our memory in different ways. When we’re stressed, the brain releases stress hormones into our bloodstream. This acute stress response was important for our ancestors to avoid dangerous situations, and it remains necessary for our daily functioning today. Genova explains that modern psychological stress affects us similarly to the physical threats our ancestors faced—the reaction an ancient human would have to being chased by a bear is the same reaction a modern human would have to committing a major social faux pas, for example.
Acute stress has a complex relationship with memory. It enhances the formation of memories related to the stressful situation by increasing attention and activating neurochemical processes that promote memory consolidation. However, this enhancement is selective, focusing on major details of the stressful situation while potentially impairing memory for peripheral details. For example, if you’re hiking in the woods and you encounter a bear, you might remember a lot about the bear’s appearance and behavior (as this is the major source of your stress), but little to nothing about details unrelated to the stressor such as the surrounding landscape.
Additionally, acute stress can interfere with retrieving memories, explaining why you may learn some information thoroughly while stressed but then be unable to remember it later.
Genova emphasizes that chronic stress, unlike acute stress, is uniformly detrimental to memory. Persistent stress continuously exposes us to stress hormones, which can desensitize our body’s stress response system and keep it permanently activated. This chronic activation inhibits the prefrontal cortex’s thinking abilities and can actually cause hippocampal neurons to die. And, since the hippocampus is responsible for consolidation, this reduces our capacity to form new memories.
How to Improve Memory
Genova offers many tips for how to improve your memory. One of the most important is to pay attention to what’s important to you, since we can remember only what we pay attention to. This requires a conscious effort, as our default state is one of inattentiveness. She recommends making a concerted effort to focus on things you want to remember—such as joyful experiences or semantic information you think you’ll need later—and avoiding multitasking as well as minimizing the distractions in your life, such as devices and social media.
Managing Stress
Genova explains that managing stress well is an important part of maintaining a healthy memory. While we can’t eliminate stress from our lives, we can influence how we respond to it. The author recommends practices like meditation, yoga, exercise, mindfulness, and gratitude to reduce chronic stress’s negative effects. She specifically notes that regular meditation and exercise can increase hippocampal size. She also recommends you get plenty of sleep—at least seven hours per night—as sleep is important for the consolidation stage of memory formation. Finally, she advises against stressing about normal forgetting, as anxiety about memory lapses can create a self-fulfilling prophecy of increased forgetfulness.
Avoiding Memory Decay
As we’ve learned, memories can also decay over time even after they’ve been stored. To combat this, Genova recommends two main strategies: repetition and adding meaning. Repetition or rehearsal can make memories extremely durable, especially when done to a point that seems excessive. Adding meaning to information by connecting it to personal narratives or existing knowledge helps preserve memories as well.
Remembering What’s on the Tip of Your Tongue
Genova also gives some specific advice on how to deal with moments when you know you have a piece of information stored in your memory, such as a word or a name, but you can’t quite seem to call it to mind—when it’s just on the tip of your tongue. Despite what many assume, using the internet to look up words that are on the tip of your tongue doesn’t weaken memory, and suffering through such states doesn’t strengthen it. To better remember names, she suggests creating elaborate associations, such as linking abstract names to concrete visual images or making meaningful connections.
For example, if your favorite book is the war novel Catch-22 but you keep forgetting the author’s name (Joseph Heller), you can think of the common phrase “War is Hell” to remember “Heller.” This similarity between the content of the book and the phrase about war will add meaning to the author’s name that makes it stick better in your memory.
Improving Prospective Memory
When it comes to improving your prospective memory, Genova recommends techniques like using to-do lists and calendars. Additionally, being specific about plans (what exactly you intend to do and when) and using visual cues in impossible-to-miss locations (like placing needed items in a spot where you know you’ll see them) can significantly improve success. Also, take note of any changes to your routine, as these can interfere with the cues you normally use to remember to do things. Try to identify things that your usual daily activities remind you to do, and if your routine is altered, come up with something else to remind you to do those things.
For example, if you have a pet hamster that you feed each morning when you eat lunch, but then one day you skip your lunch, you might also forget to feed your hamster as you miss your usual memory cue. Rather than hoping or assuming you’ll remember to do it anyway, set a reminder on your phone or put a note on your computer screen to ensure you don’t forget.
Preventing Alzheimer’s
Genova explains that most Alzheimer’s cases are the result of our genes combined with our lifestyles. Because of this, there are many things you can do to avoid developing Alzheimer’s disease. Some of these we’ve already covered, such as managing stress and getting enough sleep. Exercise—especially aerobic exercise—is also a major factor in preventing Alzheimer’s, as is mental stimulation (specifically, stimulation from learning new things, not necessarily brain exercises like puzzles or word games). Both of these promote hippocampal neurogenesis (the creation of new neurons), whereas physical and mental inactivity can lead the brain to shrink.
Genova also explains the importance of diet in Alzheimer’s prevention. She recommends diets like the Mediterranean and MIND diets, which consist of a lot of leafy greens, berries, nuts, whole grains, and healthy fat sources like olive oil and fish. She notes that, contrary to popular belief, there’s no evidence that drinking red wine reduces the risk of Alzheimer’s and points out that drinking alcohol can actually increase the risk because it can disrupt sleep. And while chocolate and coffee show some promise due to their antioxidant properties and caffeine content, more research is needed to confirm their protective effects.
How to Forget
Forgetting is a key part of remembering, as it frees up space in your brain for important information. Genova provides various strategies for intentional forgetting at three stages of the memory-formation process. First, avoid paying attention to unwanted information in the first place, so you can refrain from encoding it. Turn your attention to something else that you would like to remember.
Second, you can consciously get rid of information during the consolidation process, making a point to filter out information that you’ve encoded but don’t want to keep.
However, if you’ve already encoded, consolidated, and stored information you don’t want to remember, try to avoid exposure to cues that bring to mind those unwanted memories. Genova recommends that you consciously push it out of your mind and avoid retrieving the memory as much as possible, since every retrieval strengthens the neural connections that form the memory. If you can’t avoid the cues, consciously tell your brain to forget the information associated with those cues. This can disrupt the memory formation process and act as a neural signal to delete already existing memories.
In cases of trauma, memories can be particularly difficult to get rid of. Those with post-traumatic stress disorder often find that they can’t stop reliving or replaying memories of their experiences, which prevents them from forgetting them. To cope with this, Genova recommends a therapeutic approach that involves recalling the memories and deliberately changing them—a process known as reconsolidation—making use of the brain’s malleable reconstruction process to transform them into less painful and more neutral or positive memories.
Finally, in order to “forget” muscle memories, you have to replace them with new muscle memories. Here, the key again is repetition. You have to do it again and again until the new memory is stronger than the old one. For example, if you taught yourself to play an instrument like a recorder, you may have picked up some incorrect techniques, like placing your right hand above your left (the correct technique is to place the left hand above the right). If you decide to move up to a woodwind instrument like a clarinet, you’ll find that the right-hand-on-top technique will prevent you from playing the instrument correctly, so you’ll need to replace the muscle memories you’ve developed with muscle memory of the correct, left-hand-on-top technique.
